to be honest they look fine... but it would be quite difficult to tell if the lens is a good copy or a bad copy with this size of a photo. Truthfully we probably couldn't even tell with 2-3 full sized photos (unless I suppose they were well done test photos)

I've been hearing a lot of talk about the Sigma 18-50, and how some copies are good and some are bad.

Click to expand...

This is true of all brands including Canon and Nikon. Your photos look fine, and it's a great lens. My Sigma 18-50 f/2.8 is sharper in the corners and edges on my 20D or 40D than my Canon 24-70 L is on my 5D.